At the present time, the research and development of various dislay devices have been actively made. In particular, organic light-emitting devices have attracted attention as promising display devices, because they can provide highly bright luminescence at low voltage. For example, a light-emitting device in which an organic thin film is formed by vapor deposition of an organic compound (Applied Physics Letters, 51, 913, (1987)) has been known. The light-emitting device described in this literature is substantially improved in luminescence properties compared with conventional single-layer devices, by using tris(8-hydroxyquinolinato)aluminum complex (Alq) as an electron-transporting material and laminating a hole-transporting material (amine compound) therewith.
In recent years, the application of organic light-emitting devices to full color displays has been actively studied. However, for developing high performance full color displays, it is necessary to improve properties of each of blue, green and red light-emitting devices. For example, in regard to the blue light-emitting device, distyrylarylene compounds (DPVBi) described in “The Front Line of Organic EL Devices and Their Industrialization”, page 38 (supervised by Seizo Miyata, NTS Co. Ltd., 1998) have been widely studied. However, problems have arisen in terms of color purity, durability, luminescence luminance and efficiency, so that it has been desired that these problems should be solved.
Organic light-emitting devices realizing highly bright luminance are devices in which organic materials are applied by vapor deposition to form a laminate. The fabrication of the devices by coating is preferred from the viewpoints of simplification of manufacturing processes, processability and enlargement of their area. However, the devices fabricated by the conventional coating system, in particular, blue light-emitting devices are inferior in luminescence luminance and light-emission efficiency to the devices fabricated by vapor deposition. Accordingly, development of novel blue light-emitting device materials has been desired.